    let follow = $('b.follow');
    follow.click(function() {
        let hover_tip = $('#hover-tip');
        let that = $(this);
        that.toggleClass('followed');
        $.ajax({
            url: 'ajax/follow.php',
            type: 'GET',
            dataType: 'json',
            data: {w: 'follow',id: that.prop('id')},
        })
        .done(function(data) {
            let msg = data.sign == 'in'?'已关注':'已取关';
            hover_tip.text(msg);
            hover_tip.fadeIn();
            setTimeout(function(){
                hover_tip.fadeOut();
            },1000)
        });
    });
    let x = $('#x');
    let lv = $('#lv');
    let lv_tip = $('#lv-tip');
    lv.click(function(event) {
        lv_tip.show()
    });
    x.click(function(event) {
        lv_tip.hide()
    });
